Development of novel high-affinity nanobodies against EGFR for cancer therapy

The epidermal growth factor receptor (EGFR) is a member of a family of transmembrane tyrosine kinase receptors that plays a pivotal role in regulating diverse cellular processes such as cell proliferation, survival, migration, and differentiation. Aberrant activation of EGFR signaling has been implicated in various pathological conditions, particularly cancer, making it an attractive target for therapeutic intervention. While several anti-EGFR monoclonal antibodies have been developed and demonstrated their clinical value for the treatment of various solid tumors, smaller antibody fragments such as nanobodies (Nb) offer distinct advantages over conventional antibodies, including reduced immunogenicity and enhanced tumor penetration. In this paper, we report the isolation and characterization of two novel high-affinity Nb targeting EGFR. These Nb were identified and characterized using ELISA, flow cytometry, microscopy, and SPR. Furthermore, these Nb and bivalent Nb engineered from them were tested for their effects on cancer cell proliferation. We demonstrate that the novel Nb exhibit high affinity and potent anti-tumor activity in vitro in their bivalent form, positioning them as promising candidates for cancer treatment.